Video games have become a very popular form of family entertainment. In order to play a video game, a game cassette is first installed in a video game machine body. Game data, contained in the cassette and including video information and usually audio information, is read and outputted to a common television receiver. Accordingly, the one who wishes to play a video game must have a video game machine and a game cassette, besides a television set. Once the game cassette is installed, the player can play the game whenever and as many times as the player wishes.
However, therein lies a problem: the player has to purchase each and every game cassette he wishes to play, which can be very costly. For all the advantage that the player can play the game repeatedly, he may soon get tired of the game, or the game content may not be oriented for repeated play.
Another form of entertainment increasing in popularity is "karaoke", i.e. singing to recorded instrumental accompaniment. More and more "karaoke bars" can be seen in major cities, and karaoke machines for domestic use are becoming widely accepted. Such family karaoke machines need, by definition, karaoke music software, which can be found, for example, on video disk, video tape containing video and audio information, and music tape containing only audio information. Karaoke singers, tempted by changing trends in music, tend to purchase newly available karaoke programs, one after another. Thus, there arise problems of accumulated expenditure and limited storage space for the increasing number of karaoke programs.